// Copyright (c) 2017 CHEN Xianren. All rights reserved.
// Use of this source code is governed by a MIT
// license that can be found in the LICENSE file.

package query

import (
	"fmt"
	"strings"
	"time"
	"unicode"
	"unicode/utf8"
)

type MySQL struct {
	Engine   string
	Charset  string
	Collate  string
	ZeroTime string
}

var (
	MySQLStarter         = MySQL{ZeroTime: time.Unix(0, 0).Local().Format("'2006-01-02 15:04:05'")}
	_            Starter = MySQLStarter
)

func (mysql MySQL) CreateTable(tableName string, columns []string, temporary, ifNotExists bool) string {
	b := CreateTableBuffer(tableName, columns, temporary, ifNotExists)
	if len(mysql.Engine) > 0 {
		b.WriteString(" ENGINE=")
		b.WriteString(mysql.Engine)
	}
	if len(mysql.Charset) > 0 {
		b.WriteString(" CHARACTER SET ")
		b.WriteString(mysql.Charset)
	}
	if len(mysql.Collate) > 0 {
		b.WriteString(" COLLATE ")
		b.WriteString(mysql.Collate)
	}
	b.WriteString(";\n")
	return b.String()
}

func (MySQL) Dialect() string {
	return "mysql"
}

func (MySQL) Parameter(n bool, i int) string {
	if n {
		return ""
	} else {
		return "?"
	}
}

func (MySQL) Returning(byte, string) string {
	return ""
}

func (MySQL) Quote(s string) string {
	if len(s) == 0 || len(s) > maxLen {
		return ""
	}
	q := false
	for _, r := range s {
		switch {
		case notAllow(r):
			return ""
		case isDigit(r) || isLetter(r) || r == '$' || r == '_':
		case '\u0080' <= r && r <= '\uFFFF':
		case '\u0001' <= r && r <= '\u007F':
			q = true
		default:
			return ""
		}
	}
	if r, _ := utf8.DecodeLastRuneInString(s); unicode.IsSpace(r) {
		return ""
	}
	if !q {
		r, _ := utf8.DecodeRuneInString(s)
		q = unicode.IsDigit(r)
	}
	if !q {
		q = IsKeyword(MySQLKeywords, s)
	}
	if q {
		return "`" + s + "`"
	} else {
		return s
	}
}

func (mysql MySQL) Quoted(s string) string {
	if s[0] == '\'' {
		return s
	} else {
		return mysql.Quote(s[1 : len(s)-1])
	}
}

var (
	mysqlTypes = map[string][2]string{
		"bool":    {"BOOLEAN", "FALSE"},
		"int":     {"INT", "0"},
		"int8":    {"TINYINT", "0"},
		"int16":   {"SMALLINT", "0"},
		"int32":   {"INT", "0"},
		"int64":   {"BIGINT", "0"},
		"uint":    {"INT UNSIGNED", "0"},
		"uint8":   {"TINYINT UNSIGNED", "0"},
		"uint16":  {"SMALLINT UNSIGNED", "0"},
		"uint32":  {"INT UNSIGNED", "0"},
		"uint64":  {"BIGINT UNSIGNED", "0"},
		"float32": {"FLOAT", "0"},
		"float64": {"DOUBLE", "0"},
		// bytes, gob, interface, json, string, time, xml
	}
)

func (mysql MySQL) Mapping(_, goType string, maxSize, option int) (string, string) {
	a, ok := mysqlTypes[goType]
	switch option {
	case OptionAutoIncrement:
		a[1] = "AUTO_INCREMENT"
	case OptionAutoNow, OptionAutoNowAdd:
		if goType != "time" {
			a[1] = "DEFAULT 0"
		}
	case OptionVersion:
		a[1] = "DEFAULT 1"
	}
	if !ok {
		switch goType {
		case "time":
			switch option {
			case OptionZeroValue:
				a[1] = mysql.ZeroTime
			case OptionAutoNow:
				a[1] = "DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP"
			case OptionAutoNowAdd:
				a[1] = "DEFAULT CURRENT_TIMESTAMP"
			}
			a[0] = "DATETIME"
		case "bytes", "gob":
			if maxSize > 0 && maxSize <= 255 {
				a[0] = fmt.Sprintf("VARBINARY(%d)", maxSize)
			} else if maxSize > 16777215 {
				a[0] = "LONGBLOB"
			} else if maxSize > 65535 {
				a[0] = "MEDIUMBLOB"
			} else {
				a[0] = "BLOB"
			}
		case "json":
			a[0] = "JSON"
		default: // string, interface, xml
			if maxSize == 0 {
				a[0] = "VARCHAR(255)"
				a[1] = "''"
			} else if maxSize > 0 && maxSize <= 255 {
				a[0] = fmt.Sprintf("VARCHAR(%d)", maxSize)
				a[1] = "''"
			} else if maxSize > 16777215 {
				a[0] = "LONGTEXT"
			} else if maxSize > 65535 {
				a[0] = "MEDIUMTEXT"
			} else {
				a[0] = "TEXT"
			}
		}
	}
	return a[0], a[1]
}

var MySQLKeywords = strings.Split(strings.ToUpper(`ACCESSIBLE
ACCOUNT
ACTION
ADD
ADMIN
AFTER
AGAINST
AGGREGATE
ALGORITHM
ALL
ALTER
ALWAYS
ANALYSE
ANALYZE
AND
ANY
AS
ASC
ASCII
ASENSITIVE
AT
AUTOEXTEND_SIZE
AUTO_INCREMENT
AVG
AVG_ROW_LENGTH
BACKUP
BEFORE
BEGIN
BETWEEN
BIGINT
BINARY
BINLOG
BIT
BLOB
BLOCK
BOOL
BOOLEAN
BOTH
BTREE
BY
BYTE
CACHE
CALL
CASCADE
CASCADED
CASE
CATALOG_NAME
CHAIN
CHANGE
CHANGED
CHANNEL
CHAR
CHARACTER
CHARSET
CHECK
CHECKSUM
CIPHER
CLASS_ORIGIN
CLIENT
CLOSE
COALESCE
CODE
COLLATE
COLLATION
COLUMN
COLUMNS
COLUMN_FORMAT
COLUMN_NAME
COMMENT
COMMIT
COMMITTED
COMPACT
COMPLETION
COMPONENT
COMPRESSED
COMPRESSION
CONCURRENT
CONDITION
CONNECTION
CONSISTENT
CONSTRAINT
CONSTRAINT_CATALOG
CONSTRAINT_NAME
CONSTRAINT_SCHEMA
CONTAINS
CONTEXT
CONTINUE
CONVERT
CPU
CREATE
CROSS
CUBE
CURRENT
CURRENT_DATE
CURRENT_TIME
CURRENT_TIMESTAMP
CURRENT_USER
CURSOR
CURSOR_NAME
DATA
DATABASE
DATABASES
DATAFILE
DATE
DATETIME
DAY
DAY_HOUR
DAY_MICROSECOND
DAY_MINUTE
DAY_SECOND
DEALLOCATE
DEC
DECIMAL
DECLARE
DEFAULT
DEFAULT_AUTH
DEFINER
DELAYED
DELAY_KEY_WRITE
DELETE
DESC
DESCRIBE
DES_KEY_FILE
DETERMINISTIC
DIAGNOSTICS
DIRECTORY
DISABLE
DISCARD
DISK
DISTINCT
DISTINCTROW
DIV
DO
DOUBLE
DROP
DUAL
DUMPFILE
DUPLICATE
DYNAMIC
EACH
ELSE
ELSEIF
ENABLE
ENCLOSED
ENCRYPTION
END
ENDS
ENGINE
ENGINES
ENUM
ERROR
ERRORS
ESCAPE
ESCAPED
EVENT
EVENTS
EVERY
EXCEPT
EXCHANGE
EXECUTE
EXISTS
EXIT
EXPANSION
EXPIRE
EXPLAIN
EXPORT
EXTENDED
EXTENT_SIZE
FALSE
FAST
FAULTS
FETCH
FIELDS
FILE
FILE_BLOCK_SIZE
FILTER
FIRST
FIXED
FLOAT
FLOAT4
FLOAT8
FLUSH
FOLLOWS
FOR
FORCE
FOREIGN
FORMAT
FOUND
FROM
FULL
FULLTEXT
FUNCTION
GENERAL
GENERATED
GEOMETRY
GEOMETRYCOLLECTION
GET
GET_FORMAT
GLOBAL
GRANT
GRANTS
GROUP
GROUPING
GROUP_REPLICATION
HANDLER
HASH
HAVING
HELP
HIGH_PRIORITY
HOST
HOSTS
HOUR
HOUR_MICROSECOND
HOUR_MINUTE
HOUR_SECOND
IDENTIFIED
IF
IGNORE
IGNORE_SERVER_IDS
IMPORT
IN
INDEX
INDEXES
INFILE
INITIAL_SIZE
INNER
INOUT
INSENSITIVE
INSERT
INSERT_METHOD
INSTALL
INSTANCE
INT
INT1
INT2
INT3
INT4
INT8
INTEGER
INTERVAL
INTO
INVISIBLE
INVOKER
IO
IO_AFTER_GTIDS
IO_BEFORE_GTIDS
IO_THREAD
IPC
IS
ISOLATION
ISSUER
ITERATE
JOIN
JSON
KEY
KEYS
KEY_BLOCK_SIZE
KILL
LANGUAGE
LAST
LEADING
LEAVE
LEAVES
LEFT
LESS
LEVEL
LIKE
LIMIT
LINEAR
LINES
LINESTRING
LIST
LOAD
LOCAL
LOCALTIME
LOCALTIMESTAMP
LOCK
LOCKED
LOCKS
LOGFILE
LOGS
LONG
LONGBLOB
LONGTEXT
LOOP
LOW_PRIORITY
MASTER
MASTER_AUTO_POSITION
MASTER_BIND
MASTER_CONNECT_RETRY
MASTER_DELAY
MASTER_HEARTBEAT_PERIOD
MASTER_HOST
MASTER_LOG_FILE
MASTER_LOG_POS
MASTER_PASSWORD
MASTER_PORT
MASTER_RETRY_COUNT
MASTER_SERVER_ID
MASTER_SSL
MASTER_SSL_CA
MASTER_SSL_CAPATH
MASTER_SSL_CERT
MASTER_SSL_CIPHER
MASTER_SSL_CRL
MASTER_SSL_CRLPATH
MASTER_SSL_KEY
MASTER_SSL_VERIFY_SERVER_CERT
MASTER_TLS_VERSION
MASTER_USER
MATCH
MAXVALUE
MAX_CONNECTIONS_PER_HOUR
MAX_QUERIES_PER_HOUR
MAX_ROWS
MAX_SIZE
MAX_UPDATES_PER_HOUR
MAX_USER_CONNECTIONS
MEDIUM
MEDIUMBLOB
MEDIUMINT
MEDIUMTEXT
MEMORY
MERGE
MESSAGE_TEXT
MICROSECOND
MIDDLEINT
MIGRATE
MINUTE
MINUTE_MICROSECOND
MINUTE_SECOND
MIN_ROWS
MOD
MODE
MODIFIES
MODIFY
MONTH
MULTILINESTRING
MULTIPOINT
MULTIPOLYGON
MUTEX
MYSQL_ERRNO
NAME
NAMES
NATIONAL
NATURAL
NCHAR
NDB
NDBCLUSTER
NEVER
NEW
NEXT
NO
NODEGROUP
NONE
NOT
NOWAIT
NO_WAIT
NO_WRITE_TO_BINLOG
NULL
NUMBER
NUMERIC
NVARCHAR
OF
OFFSET
ON
ONE
ONLY
OPEN
OPTIMIZE
OPTIMIZER_COSTS
OPTION
OPTIONALLY
OPTIONS
OR
ORDER
OUT
OUTER
OUTFILE
OWNER
PACK_KEYS
PAGE
PARSER
PARTIAL
PARTITION
PARTITIONING
PARTITIONS
PASSWORD
PERSIST
PHASE
PLUGIN
PLUGINS
PLUGIN_DIR
POINT
POLYGON
PORT
PRECEDES
PRECISION
PREPARE
PRESERVE
PREV
PRIMARY
PRIVILEGES
PROCEDURE
PROCESSLIST
PROFILE
PROFILES
PROXY
PURGE
QUARTER
QUERY
QUICK
RANGE
READ
READS
READ_ONLY
READ_WRITE
REAL
REBUILD
RECOVER
RECURSIVE
REDOFILE
REDO_BUFFER_SIZE
REDUNDANT
REFERENCES
REGEXP
RELAY
RELAYLOG
RELAY_LOG_FILE
RELAY_LOG_POS
RELAY_THREAD
RELEASE
RELOAD
REMOVE
RENAME
REORGANIZE
REPAIR
REPEAT
REPEATABLE
REPLACE
REPLICATE_DO_DB
REPLICATE_DO_TABLE
REPLICATE_IGNORE_DB
REPLICATE_IGNORE_TABLE
REPLICATE_REWRITE_DB
REPLICATE_WILD_DO_TABLE
REPLICATE_WILD_IGNORE_TABLE
REPLICATION
REQUIRE
RESET
RESIGNAL
RESTORE
RESTRICT
RESUME
RETURN
RETURNED_SQLSTATE
RETURNS
REVERSE
REVOKE
RIGHT
RLIKE
ROLE
ROLLBACK
ROLLUP
ROTATE
ROUTINE
ROW
ROWS
ROW_COUNT
ROW_FORMAT
RTREE
SAVEPOINT
SCHEDULE
SCHEMA
SCHEMAS
SCHEMA_NAME
SECOND
SECOND_MICROSECOND
SECURITY
SELECT
SENSITIVE
SEPARATOR
SERIAL
SERIALIZABLE
SERVER
SESSION
SET
SHARE
SHOW
SHUTDOWN
SIGNAL
SIGNED
SIMPLE
SKIP
SLAVE
SLOW
SMALLINT
SNAPSHOT
SOCKET
SOME
SONAME
SOUNDS
SOURCE
SPATIAL
SPECIFIC
SQL
SQLEXCEPTION
SQLSTATE
SQLWARNING
SQL_AFTER_GTIDS
SQL_AFTER_MTS_GAPS
SQL_BEFORE_GTIDS
SQL_BIG_RESULT
SQL_BUFFER_RESULT
SQL_CACHE
SQL_CALC_FOUND_ROWS
SQL_NO_CACHE
SQL_SMALL_RESULT
SQL_THREAD
SQL_TSI_DAY
SQL_TSI_HOUR
SQL_TSI_MINUTE
SQL_TSI_MONTH
SQL_TSI_QUARTER
SQL_TSI_SECOND
SQL_TSI_WEEK
SQL_TSI_YEAR
SSL
STACKED
START
STARTING
STARTS
STATS_AUTO_RECALC
STATS_PERSISTENT
STATS_SAMPLE_PAGES
STATUS
STOP
STORAGE
STORED
STRAIGHT_JOIN
STRING
SUBCLASS_ORIGIN
SUBJECT
SUBPARTITION
SUBPARTITIONS
SUPER
SUSPEND
SWAPS
SWITCHES
TABLE
TABLES
TABLESPACE
TABLE_CHECKSUM
TABLE_NAME
TEMPORARY
TEMPTABLE
TERMINATED
TEXT
THAN
THEN
TIME
TIMESTAMP
TIMESTAMPADD
TIMESTAMPDIFF
TINYBLOB
TINYINT
TINYTEXT
TO
TRAILING
TRANSACTION
TRIGGER
TRIGGERS
TRUE
TRUNCATE
TYPE
TYPES
UNCOMMITTED
UNDEFINED
UNDO
UNDOFILE
UNDO_BUFFER_SIZE
UNICODE
UNINSTALL
UNION
UNIQUE
UNKNOWN
UNLOCK
UNSIGNED
UNTIL
UPDATE
UPGRADE
USAGE
USE
USER
USER_RESOURCES
USE_FRM
USING
UTC_DATE
UTC_TIME
UTC_TIMESTAMP
VALIDATION
VALUE
VALUES
VARBINARY
VARCHAR
VARCHARACTER
VARIABLES
VARYING
VIEW
VIRTUAL
VISIBLE
WAIT
WARNINGS
WEEK
WEIGHT_STRING
WHEN
WHERE
WHILE
WITH
WITHOUT
WORK
WRAPPER
WRITE
X509
XA
XID
XML
XOR
YEAR
YEAR_MONTH
ZEROFILL`), "\n")
